package com.xuan.juc.unsafe;

import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.UUID;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.locks.Condition;

// ConcurrentModificationException
public class MapTest {
    public static void main(String[] args) {
//        Map<String,String> map = new HashMap<>();

//        Map<String,String> map = Collections.synchronizedMap(new HashMap<>());

        Map<String,String> map = new ConcurrentHashMap<>();

        for (int i = 0; i < 30; i++) {
            new Thread(()->{
                map.put(Thread.currentThread().getName(), UUID.randomUUID().toString().substring(0,5));
            }).start();
        }

    }
}
